Re: [Bug-tar] Skipped files with --listed-incremental after rename

[Joerg Schilling]

>>From glancing over the documentation for star 1.5 beta (which doesn't have a
>complete implementation of incremental backups yet), it saves all the inode
>metadata and I guess uses that 

The implementation for doing incremental backups is complete, only the 
implementation for incremental restores is currently missing.

Star basically uses the same method as ufsdump/ufsrestore. So this is a 
technique that is ~25 years old and still accepted to be correct enough.


If you compare the incremental method used by GNU tar with the method used by
star, the following problems show up for GNU tar:

-       GNU tar supports only level 0 & level 1
        Star supports any number of dump levels.

-       More information than simply "mount point", "Dump level" and "Dump Date"
        is needed to be saved between diferent dumps by GNU tar.

-       GNU tar archives a complete directory hierarchy if a directory is 
        renamed. This increases the needed tape space and may cause a 
filesystem 
        overflow during extract (when the needed deletion is detected after the
        copy has been extracted from tape).
        Star only archives the inode meta data.

-       GNU tar archives the complete file content if only a chmod has been done
        with the file.
        Star only archives the inode meta data.

-       GNU tar does not archive ACLs, File flags and Extended file attributes.
        Star does archive all of them if you tell it to do so.


Now that I introdced the inode number array for directory content in 
star-1.5a31, the incremental restore algorithm has become much simpler. There 
is a 90% chance that a first working version is ready within two weeks.

Jörg

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